The invention relates to a centrifuge.
A centrifuge of this type is known from European Patent Document EP-A-0 640 398.
European Patent Document 886 514 C also shows a centrifuge whose first separating disk is pushed on an interior inlet tube and whose second separating disk is pushed over the first separating disk.
One centrifuge of this type is known from German Patent Document DE 38 33 063 C1. This document shows a centrifuge having a separating disk for draining liquids from a centrifugal drum The separating disk having two draining ducts which, starting from the periphery of the separating disk, first extend spirally inward and then perpendicularly upward and which each have a restriction point whose cross-section is variable by means of an axially adjustable restriction body.
The construction of the axially adjustable restriction body has been successful per se. However, if two separating disks are used instead of a single separating disk in order to drain two liquids of different densities, it is necessary to, in each case, assign separate restriction bodies to the two separating disks. If, during the operation, the centrifuge is acted upon by different amounts of liquids, it is also necessary to adjust the restriction bodies each separately, in the case of the two separating disks, in order to adapt them to the changed amount of liquid. Such a separate adjustment is difficult because the restrictions have to be adjusted with respect to one another such that they do not influence one another disadvantageously.
In view of these problems, it is an object of the invention to further develop the centrifuge of the above-mentioned type such that a constructively simple alternative, which can be handled in an uncomplicated manner, is created for the axial adjustment of the restriction points.
The invention achieves this goal.
As a result of the idea of the rotatable restriction body, an alternative possibility is created for adjusting the restriction cross-section which can be implemented in a constructively simple manner and which, because of the elimination of the axial adjustment of the restriction body, permits a particularly compact construction of the centrifuge while its handling is easy.
A sleeve is preferably fitted upon one of the rotary-cut disks and projects with its circumference into the outlet opening of the draining duct. As a result of the projection into the outlet opening, the sleeve is capable of partially closing the outlet opening and in this manner implementing the restriction effect. The construction as a cylindrical sleeve also permits a simple adjustment of the restriction cross-section by means of a handle which is mounted on the sleeve and can be gripped from the outside.
The changeability of the restriction effect can be implemented in an uncomplicated manner by providing the cylindrical sleeve with circumferential openings or (aperture-type) recesses xe2x80x94for example, in the axial end areaxe2x80x94, which are distributed along the circumference such that, when the sleeve is rotated on the separating disk, they more or less cover the outlet opening of the at least one restriction point.
In addition to the above-mentioned advantages and according to another idea of the invention, the rotatability of the restriction body provides a simple possibility for solving the problems of coordinating the adjustment of the restriction cross-sections in the case of two separating disks. For this purpose, the circumferential openings or recesses of the sleeve are coordinated such that, when the sleeve is rotated on the separating disk, the cross-sections of the restriction points of several different separating disks, as a function of the flow of liquid into the centrifuge, are variable in a mutually coordinated manner. The mutual coordination of the recesses or openings in the sleeve is determined empirically. Theoretically, sleeves can thereby in each case be implemented for each application which have a suitable xe2x80x9caperture characteristicxe2x80x9d.
If the recesses in the circumference of the sleeve are constructed at both axial ends of the cylindrical sleeve so that, in each axial end area, one of the restriction points respectively is changed when the sleeve is rotated, the coordinated adjusting of two rotary-cut disks will be permitted.